Engine starter



March 18, 1924. i 1,487,063

. J. A. HOLTON Filed Oct. 26. 1918 Patented Mar. 18, 1924.

UNITED STATES PATENT OFFICE.

JESSE A. HOLTON, OF BOSTON, MASSACHUSETTS, ASSIGNOR, BY MESNE ASSIGNMENTS,

TO THE FIRST NATIONAL BANK OF BOSTON, TRUSTEE,

A CORPORATION.

ENGINE STARTER.

Application filed October 26, 1918. Serial No. 259,866.

To all whom it may concern:

Be it known that I, Jesse A. HoL'roN, a citizen of the United States, residing at Boston, in the county of Suffolk and State of Massachusetts, have-"invented certain new and useful Improvements in Engine Starters, of which the following is a specification.

This invention relates to engine starters and with respect to certain more specific features thereof to automatically completeable and interruptable transmissions therefor.

It is one of the objects of the present invention to provide an extremely compact 1 power transmitting device whereby a driving shaft, such, for instance, as a motor armature shaft, may be automatically engaged with an engine driven member, such, for instance, as a fly wheel, and power transmitted 0 from the former to engine its initial compression.

Another object of the present invention resides in the improved arrangement of parts whereby a spring cushionin effect may be obtained and the diametrica dimensions of the transmission maintained at a minimum.

Still another object resides in the provision of meansfor preventing the drivin enaging member or shiftable pinign rom rifting into accidental engagement with the engine driven member or fly wheel.

Other objects will be in part obvious and in art pointed out hereinafter.

tion of elements and arrangement of parts which will be exemplified by the construction hereinafter set forth and the scope of the application of which will be indicated in t e following claims.

In the accompanying drawings wherein is shown one of various possible embodiments of the invention- .Fig. 1 is a view of an engine starter, certain of the parts being in longitudinal horizontal section to show more clearly the interior construction; and

Fig. 2 is an elevational view of the shiftable sleeve showing the means designed to prevent drifting of the pinion into accidental engagement with the fly, wheel.

ferring now more particularly to the drawing'sfthere is indicated at 1 an electric motor, having a. casing 2 and an armature the latter to give the.

. each other he invention accordingly consists of the various features of COIlStI'llCtlOIl, combmashaft extension 3 projecting beyond the easing. The armature shaft is stepped in three lengths, asshown clearly in Fig. 1, the first length 4 adjacent the casing'being of largest diameter and serving as an end bearing for the shiftable sleeve which will later be described. An intermediate length 5 of the shaft extension is provided with a thread 6, and the outer length 7 is of considerably reduceddiameter and penetrates the end of the shiftable sleeve. It will be noted'that two shoulders are provided on the shaft'extension, one of which is indicated at 8, and the other at 9. A shiftable sleeve 10 is interiorly threaded and adapted to co-operate with the threaded length 5 of the shaft extension. At the inner end of the sleeve it is provided with an enlarged bore 11 terminating in a shoulder 12. This bore permits the sleeve and the shaft extension to telescope with the shoulder 12 abuts the shoulder 8 of the shaft extension. Opposing this telescopic movement,ho wever, is a coiled compression spring 13 surrounding the reduced outer length 7 of the shaft extension and housed by the'outer end of the sleeve 10, which is bored, as indicated at 15, to receive the spring. outer end cap 16 through which the reduced outer end 7 of the shaft extension projects, and a nut and washer, are provided at the extreme end of the shaft to limit the outward movement of the sleeve. It is against the inner surface of this cap that the spring 13 bears, the same reacting against the shoulder 9 formed between the threaded length 5 and the reduced length 7 of the shaft.

The sleeve 10 is exteriorly threaded, as indicated at 20, and loosely mounted thereon is an interiorly threaded pinion or driving engaging member 21, the inner end of the cap 16 servingas a limiting stop and determining the outer position of the pinion relatively to the sleeve and shaft. At the inner end of the sleeve there is a stop 22 against which the pinion is brought to bear in its longitudinal shifting movement. I

The internal combustion engine is indicated at having a crank shaft 31 and an engine driven member or fly wheel 32. It willbe noted that with theparts in inactive position, a shown in Fig. l,'the pinion 21 15 out of engagement with the fly wheel 32,

to a limited extent'-that is, until The sleeve 10 is provided with an a distance of perhaps a quarter or threeeighths of an inch, and that the stop 22 is pposite the teeth of the fly wheel.

When it is desired to start the engine, current is supplied to the electric motor by closing a switch (not shown) and including a storage battery (not shown) in an electrical circuit with the motor, thus energized, the armature shaft extension 3 will be rotated. The spring 13 functions at this time to exert sufficient pressure so that the friction created between the thread 6 and the sleeve 10 will cause the sleeve to rotate with the shaft. The pinion 21, however, being loosely threaded on the exterior of the sleeve, and being inert, will travel longitudinally toward and into engagement with the fly wheel 32 until further movement i restricted by its engagement with its limiting stop 22. At this point of operation, and with the fly wheel offering resistance, the active tooth of the pinion will be brought to bear rotatively against the (re-operating tooth of the fly wheel gear, and the resistance offered being sufficient to overcome the resistance of the friction created by the spring 13, continued movement of the armature shaft will cause a longitudinal movement of the sleeve inwardly relatively to the armature shaft. The spring 13, of course, opposes this movement and this opposition progressively increases as the spring is more and more compressed. Finally, the stop shoulder 12 is brought into engagement with the stop shoulder 8 and the starting transmission is then established for rotary effort. Continued movement of the armature shaft rotates the sleeve and pinion with the shaft and the fly wheel is rotated to start the engine. When the engine starts the speed of the fly wheel is greatly increased over that contributed to it by the motor and the pinion is caused to overtravel the sleeve until out of engagement with the fly wheel. As a matter of practical effect, the pinion is kicked out to its stop 16 and by its momentum picks up the sleeve and carrie it to the position shown in Fig. 1. If there is any tendency for the pinion to drift back into engagement with the fly wheel by reason of vibration or other causes, this may be overcome by cutting the thread a few thousands smaller up to within say, one eighth inch of the fly wheel, as indicated in Fig. 2 at 40. This will not interfere with the shifting movement of the pinion in it starting and power transmission completing operation, and, in fact, is found beneficial, due to the fact that the decreased diameter of the sleeve where the threads are cut smaller provides an easier fit for the pinion. The increase in diameter of the threads on the sleeve from the undercut portion to the normal diameter provides a small inclined shoulder sufiicient to arrest any accidental the motor being 7 shifting of the pinion into contact with the driven member while the transmission is out of driving engagement.

Attention is directed to the impact ielieving s ring in a chamber carried by the rotor o the dynamo electric machine and also to the reinforcing of this spring by the shaft portion 7. Distortion is prevented by this construction and the device rendered compact and of good appearance. Applicant believes he is the first to provide a structure of this character in apparatus for engine starting.

As many changes could be made in the above construction and as many apparently widely different embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter set forth in the foregoing description or shown in the accompanying drawings, shall be interpreted as illustrative and not in housing of the .a limiting sense.

Having thus described my invention what I claim as new and desire to secure by Letters Patent of the United States is:

1. In a starting device, the combination with a member to be driven, of a driving member with an exteriorly threaded portion, a sleeve threaded thereon and having an exteriorly threaded portion, and a pinion threaded on said sleeve, the thread on the pinion and the thread on the exteriorly threaded portion of the sleeve being relatively so constructed and arranged as to oppose the vibratory shifting of the pinion into contact with the driven member.

2. In a starting device, the combination with a member to be driven, of a driving member with an exteriorly threaded portion, a sleeve threaded thereon, and a pinion threaded on said sleeve, said sleeve having a thread which increases in diameter slightly to oppose the vibratory shifting of the pinion into contact with the driven member.

3. In an engine starter, in combination, a casing, a shaft portion extending beyond said casing, the said extending portion comprising a stop shoulder of one diameter, a threaded length of lesser diameter and an outwardly continuing length of still lesser diameter, a sleeve threaded on said portion having a closed end and a bore adapted to receive a spring in position to bear between the closed end of the sleeve and the shoulder formed at the outer end of the threaded length, said spring, and a pinion loosely threaded on said sleeve, 'said sleeve having a thread which increases in diameter slightly at a definite region.

4. In a starting device, the combination with a member to be driven, of a driving member with an exteriorly threaded ortion, a shoulder on said portion, a sleeve t eaded thereon and having a shoulder and a closed outer end, a second shoulder on said shaft portion and a reduced end extending through s ring means within said closed interior the closed end of said sleeve, a spring coiled chamber to cushion the impact of driving around said reduced end, bearing against connection, and a driving engaging memsaid closed end and reacting against said her supported by said control member.

second shoulder, and a pinion loosely thread- 7. In a starting apparatus, in combination,

ed on said sleeve. a driven member, a. driving engaging mem- 5. In a device of the character described, ber, a driving member comprising a cylinin combination, a member to be driven, a drical portion havinga stop shoulder, an exdriving member having a portion compristeriorly threaded portion of smaller diaming a stop shoulder of one diameter, a eter andacylindrical portion of still smaller threaded length of lesser diameter and an diameter, an exteriorly and interiorly threadoutwardly continuing len h of still lesser ed control member having stop shoulders diameter, a sleeve threade on said portion at the ends of the exterior threads, a bored having a closed end and a bore adapted to chamber at one end adapted to slide over receive a spring in position to bear between the large cylindrical portion of said driving the closed end of the sleeve and the shoulder member to permit the bottom of said chamformed at the outer end of the threaded her to abut said stop shoulder of the driving length, said spring, and a. pinion loosely member, a closed chamber at the opposite threaded on said sleeve.

6. In a device of the character described, said portion of smallest diameter of said in combination, an element to be driven, a. driving member extends, spring means entransmission normally out of engagement cased in last said chamber to cushion the with said element comprising a partially shock of driving connection, and means threaded drivin member, an interiorly and forming a part of the exterior threads of exteriorly threa ed control member sup rtsaid control member to oppose the vibratory ed thereon having exterior stop shou ders shifting of the drivin engaging member at both ends, an open interior chamber at into contact with the driven member while one end suitable for sliding over a portion the apparatus is normally out of driving enof the driving member, a closed interior gagement. chamber at the o posite end through which a portion of said driving member extends, JESSE A. HOLTON.

end of said control member through which 

